TULSA, Okla. (AP) - A group planning to build an American Indian cultural center along the Arkansas River in southwest Tulsa has failed to meet a fundraising deadline and must raise $22 million by the end of the year or risk losing its lease.

"It's been a slow process to raise the money we need," said Monetta Trepp, a member of the board of directors of the National Indian Monument and Institute.

The deadline for raising $3 million was June 30, which had been extended from Dec. 31.

The group submitted its list of contributions and pledges, totaling $1.74 million, to the River Parks Authority on July 12.

It also provided a recent letter from a restaurant company, HealthTrak, promising to give $1.5 million, but authority members wanted to review the company's financial report before agreeing to another extension.

HealthTrak representatives indicated they want to contribute $10 million ultimately to place a restaurant in the center.

The lease requires the group to raise the entire $22 million cost of the project's first phase by the end of this year.

The first phase would include a theater, a restaurant and mixed-purpose space for arts festivals and other cultural events. It also would have office space for the National Indian Monument and Institute and other American Indian organizations.

A proposed second phase, with a projected price tag of about $35 million, would include a museum and a National American Indian Monument.

"We're optimistic that once we get over this hurdle, the rest of the funding will come together," said Cole Perryman, chairman of the National Indian Monument and Institute's fundraising committee.

The group has prepared a scaled-back version of the first phase that would cost about half of the original, just in case, he said.

Project leaders have since said their fundraising has been hampered because the cultural center's design has been in flux due to the site's unique topography.

The Vision 2025 countywide sales-tax initiative set aside $2 million for necessary infrastructure, but that money is not available until the private fundraising efforts produce results.